The goals of this research are to investigate new methods to determine protein structure, measure protein-protein structure and binding, and separate and identify different protein conformers using mass spectrometry methods. Both solution-phase and gas-phase studies will be performed. From differences in structure or binding interactions in these two phases, information about how solvent influences both protein conformation and specific intermolecular interactions between proteins can be determined. This information could potentially enhance computational methods for determining protein structure and folding and for mass spectrometry methods for drug discovery. A sensitive, high throughout method for determining protein conformation could greatly improve researchers' ability to discover functions of proteins and identify new structure based medicines. Tandem mass spectrometry experiments of noncovalent complexes will be investigated. These studies can provide structural information that is difficult or not obtainable by other methods. Specific aims include 1) develop a potentially sensitive and rapid method for determining protein conformation using solution-phase H/D exchange with electron capture dissociation for identifying exchange sites with individual amino acid resolution, 2) evaluate both solution-phase and gas-phase binding interactions in a protein-protein complex and 3) investigate high-field asymmetric waveform ion mobility spectroscopy as a rapid and sensitivity method for protein conformational analysis. It is hoped that these studies will provide a firm basis for relating structural information of biopolymers and noncovalent complexes determined from gas-phase experiments back to the structures of the ions in bulk solution. This research is aimed at developing new methods for rapidly determining the folded structure of proteins, how they interact with other proteins, and how surrounding solvent molecules can effect these interactions. These studies can provide important new information that can be useful for understanding diseases in which proteins misfold, including Alzheimer's disease, cystic fibrosis, spongiform encephalopathies (e.g., Mad Cow or Creutzfeldt Jakob disease), and even some cancers. In addition, the studies of protein-protein interactions can potentially provide a faster and more general method that could significantly improve the discovery of new drugs for disrupting aberrant complexes that are frequently associated with human disease.